Annoyed with myself that I cannot sort this......
had to replace the rear brake drum sprocket, so also fitted new chain and gearbox sprocket obviously needing complete dismantling of primary side.
spent time welding up two sockets so that I could get correct torque on gearbox sprocket nut.
on reassembly when the clutch centre nut is torqued up to spec it completely locks the kickstart. Loosening said nut, way below spec, loosens the kickstart. All the parts are as per illustrations and correctly fitted.
nothing has been done to the gearbox other than to lock the rear wheel for tightening nuts.
polite suggestions please !!!!!!
Is the new gearbox sprocket longer than the original? Or does it fit further/different on the main shaft?. What about leaving everything as new except replace the old sprocket, try again.
Best of luck, report back.
Are you sure you haven`t sheared the clutch location circlip on the mainshaft which can happen if you use the torque figure in the book. Can you turn the engine over by pushing the bike while in gear (with spark plugs removed) or is the clutch drum hard against the back of the primary inner cover locking the motor up?
Do the clutch up to 40 foot pounds and use nutlock.
Alan's suggestion applies if you have a Commando.
Attachment shows internals.
Dominator box is very similar minus longer mainshaft and circlip grove.
Do you have a Commando or Dominator???
Its possible that the spline stop in the clutch (actually in the spider) has disintegrated and the clutch is now jamming the shaft and sleeve gear together as you tighten it all up. It hapened to me with an orriginal Norton part that had lasted 58 years . Al O's option is the most likely. I seem to remember a spacer in that assembly , --could have been left out or fitted wrong side of sprocket?
delayed replies to you all....apologies.
Alan O.....sprocket matches....just as well as it was NOC shop and I’d hate to upset Neil.
Alan H/ Philip H....should have said 88 slimline....didn’t realise the Commando shaft was diff.
Rob...see below it’s a gearbox issue.
BACKGROUND....OK the reason for sprocket changes and chain replacement was transmission problems on a club run. The rear chain turned into a piece of elastic. The 88 has a full rear chain case so it was question of checking slack and adjusting as the ride progressed. Eventually the clutch cable snapped and Carole Nash got me home. Inspection showed that the rear sprocket was badly chewed so I guess the chain had some really tight spots.
So the cause of kickstart jamming ? The sleeve gear/main shaft bearing had moved out of its housing causing things to lock up.
I can’t find any movement between the the sleeve gear and the bearing although there is may be a clue in the attached photo. There are ‘lumps’ in the nylon? Ball bearing retaining ring.
there is some play in the sleeve gear on the main shaft but not sure if too excessive or normal bush tolerence.
what do I need to replace? Just the bearing?
thanks again for support. Regards JMB
Seems like a simple case of replace the bearing with a new one to the right spec ,perhaps some bearing fit locktite as well.. Also a new chain .Its also worth checking that the gearbox top bolt which is a bit like a coach bolt ,has not seized in the alloy tunnel and can be moved inwards towards the primary case, which is necessary to allow the proper adjustment of the primary chain.
OK , so this has been a slow, when time allows job.
fitted new gearbox sleeve gear bearing, making sure it was flush. Carefully rebuilt gearbox. All working fine.
reassembled primary side and a few turns of the clutch centre nut, virtually just over hand tight and its locked. In fact the clutch drum sprocket is rubbing against the inner primary chain case.
Cannot see any reason.
So to help my struggling brain......with the sleeve gear fitted through the bearing and the spacer and seal fitted, when the sprocket and nut,washer,screw are tightened to spec...surely the bearing is sandwiched in the casing. Therefore the should be correct amount of mainshaft reaching the clutch area....or not???
Can’t see the wood for the trees so all suggestions welcome.
thanks for your time. JMB
PS admission, I have not used loctite ...not a fan. Should I in this case?
Have you checked that the stop in the clutch center (spider) is still intact (as per my earlier post.)If its not there then the clutch will migrate up the shaft and jam against the sleeve gear or case. If it looks suspect you will have to completely dismantle the clutch center and race plate to replace the spider. RGM about £60.
Robert, thanks for reply. Yes I did check the clutch centre/spider as you suggested but see I didn’t acknowledge that.
so, the spline ‘stop’ in the clutch centre is good....however if I measure from that stop to the end of the spline I get a measurement 2mm longer than the available spline on the mainshaft that extends into the primary case.
having pored over the gearbox diagram I can only assume that the sleeve gear bearing is/has moved, although I dont quite see how. Feel like giving the mainshaft a good thump!!!!!!
As regards loctite....if I have to strip gearbox to reseat the bearing....thus having to heat things up....how does the loctite respond?? Will it run everywhere or dry off before I can get the bearing in etc etc??
thanks again, JMB
Heat will affect the grip of the locktite but just using inertia to get the bearing out will not be enough .May have to get brutal. Definately a good puzzle , Does the box work fine before the installation of the clutch? Cant imagine it would if the bearing was not fully in. In my head still thinking you have a clutch issue!!.I would be thinking of making up a 2mm + spacer to fit in the spider. I like a good bodge! I would try heating the case up with a blowlamp around the bearing and while hot fitting the clutch and tightening up the nut to see if the bearing will move further into the case. .If it all goes ti**s up don't blame me!. Just had a thought,RGM are selling spiders (seconds quality) very cheap, use as a tool to pull the bearing up ?.and as a reference as to how a good register/stop should look?.
hello now my question why was there welding done in the first place now there should be nothing in the gear box to lock up the kick start And hears why the gearbox sprocket is fitted to the sleeve gear and the sprocket nut is left hand thread and should done up to the locking washer and the locking screw holes are showing so you then fit this locking screw can be fitted and the sleever gear dose not interfere with the main shaft And the Spider with in the clutch dose not interfere with the main shaft as its mounted in rubber and its splines are shanfered so when the main shaft center nut is tightened up its the can go not farther , So I cannot see what locking the kick start as their should be nothing to do this So too me someone as not assembled the gear box cluster in the right way ,So too me is a right mess the only answer is to disassemble the gearbox and inspected it methodically and then find out what the fault is , yours anna j
I'm Afraid Anna is not reading all your posts . Sorry to keep banging on about the spider.but when mine failed it did the same, Looking inside it all looked very reasonable but it was still able somehow to overide the end of the mainshaft .After studying some new ones on the internet I realised that the new ones( RGM ) were of a different internal design and the "stop" now resisted both end of spline AND the shoulder at the end of spline,this was different to my orriginal spider so I can only assume this is a known problem and has been modified to make stronger. I probably did not help by doing up the nut a bit too tight. As far as I am aware there is not a taper on the shaft as previously I had been able to just pull the clutch off by hand. After the stop became damaged it certainly felt like there was a taper as all was getting mangled , and a puller was needed. Perhaps Anna's is on its way too??.
hello rob and others do not over tighten the sprocket nut you supposed to do up the nut as far as it will go without much presser then turn it back to fit the locking screw just like doing up the center wheel bearing locking nut on your car you nip it up as far as it will go then you turn it back to fit the locking split pin your anna j
Part if the problem is that I don't think there is a good public domain sectional drawing of how the gearbox and clutch parts all fit together. So it's not easy to inspect for faults. I've never seen one. And nobody seems to know for certain exactly how the various felt washers fit.
It is possible to fit the gears wrongly. In the past when following the dreaded Haynes manual, it described the fitting of the 4th gear on the layshaft back to front. And it would run like that. Not that easy to do the same with the others . The kickstart pawl will work happily (for a time) upside down. The change spring will fit upside down . Did someone tell me these things?----errr--no !. Any other classic boobs you know of?. Come on fess up.Its for a good cause. May help John. And we all need to laugh !.
thanks again for all your replies.
Rob....intense spider its going to be then!
Anna....all you queries where answered in my earlier posts. Sorry but the sleeve gear sprocket is NOT hand right but in the region of 70-80 ft lbs.
David...couldn’t agree more. Many of the small fiddly issues never have suitable diags.
spider update to follow.
If it makes you feel any better I have a similar problem on a single I am building, (one of Mikes engines) the clutch won’t fit without fouling the chaincase, I thought I had the wrong mainshaft, but I don’t, it’s the GT 165 (laydown). I fitted a new clutch I had for another project and sadly .... still no joy. I’m tempted to fit a longer twins mainshaft to give me the clearance, but you won’t have that option with an AMC type box! It’s all part of the joys of owning an old bike!
i wonder if the clearance in the spiders changed over the years?
Hi John, If you look on E Bay there is an ad for new spiders for £20 ,and more to the point some usefull photos of the spline stops.. which form a complete circle. Does yours look the same?. Or are they like my old one with gaps?.and a distingct lack of integrity!.